Display substrate and preparation method thereof, and display device

ABSTRACT

A display substrate includes a display region and hollowed-out grooves provided at a periphery of the display region. The display substrate includes a first organic base layer, a light-emitting unit provided on the base structure layer and located at the display region; the first organic base layer is provided with a groove structure located between the hollowed-out grooves and the display region. The display substrate further includes a first inorganic package layer for covering the light-emitting unit and the groove structure.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the priority of Chinese PatentApplication No. 201910810440.6 filed to the CNIPA on Aug. 29, 2019, thecontent of which is hereby incorporated by reference.

TECHNICAL FIELD

The present disclosure relates to, but is not limited to, the field ofdisplay technology, and particularly relates to a display substrate anda preparation method thereof, and a display device.

BACKGROUND

Organic Light-Emitting Diode (OLED) display is a display and lightingtechnology developed in recent years, which has the advantages of highresponse, high contrast and flexibility etc., and is considered to havea wide application prospect. In the flexible display, the deformable andbendable characteristics of OLED display devices further reflect theadvantage of the OLED display.

As one of the important development directions of flexible displayproducts, stretchable display devices have gained a wide attentionbecause they can be applied to wearable equipment and even clothing. Inthe stretchable OLED product, the OLED display panel includes multipledisplay regions arranged in an array, each display region is providedwith multiple OLED light-emitting units, and a hollowed-out groove isformed between adjacent display regions, so that when the display panelis stretched, the hollowed-out groove is deformed to prevent thestretching from affecting the display of the display regions.

In stretchable OLED display products, water and oxygen easily invadeinto OLED light-emitting units, affecting the service life of thedisplay panel.

SUMMARY

The following is a summary of the subject matter described in detailherein. This summary is not intended to limit the protection scope ofthe claims.

In an aspect, an embodiment of the present disclosure provides a displaysubstrate, which includes a display region and hollowed-out groovesprovided on a periphery of the display region, the display substrateincludes a base structure layer and a light-emitting unit provided onthe base structure layer and located in the display region, the basestructure layer includes a first organic base layer, the light-emittingunit is provided on the first organic base layer, the first organic baselayer is provided with a groove structure located between thehollowed-out grooves and the display region, and the display substratefurther includes a first inorganic encapsulation layer covering thelight-emitting unit and the groove structure.

In some possible implementations, the base structure layer furtherincludes a barrier layer and a second organic base layer, the barrierlayer is disposed on a side of the first organic base layer facing awayfrom the light-emitting unit, and the second organic base layer isdisposed on a side of the barrier layer facing away from the firstorganic base layer.

In some possible implementations, the thickness of the base structurelayer is 10 μm to 50 μm, the thickness of the second organic base layeris 8 μm to 12 μm, the thickness of the barrier layer is 0.05 μm to 2.5μm, and the thickness of the first organic base layer is 8 μm to 12 μm.

In some possible implementations, the groove structure includes a firstgroove exposing the barrier layer, and the first inorganic encapsulationlayer is in direct contact with the barrier layer at the first groove.

In some possible implementations, the groove structure further includesa second groove located between the first groove and the display region,and the depth of the second groove is smaller than the thickness of thefirst organic base layer.

In some possible implementations, the groove structure includes multiplesecond grooves, the multiple second grooves are sequentially providedbetween the first grooves and the display region, and the depths of themultiple second grooves are sequentially reduced in a direction from thefirst grooves toward the display region.

In some possible implementations, the longitudinal section shapes of thefirst groove and the second groove are both in an open shape withgradually increasing openings, and the longitudinal section is a sectionperpendicular to the length direction of the first groove or the secondgroove.

In some possible implementations, the depth of the second groove is ¼ to½ of the thickness of the base structure layer.

In some possible implementations, the spacing between adjacent secondgrooves is greater than 20 μm, the spacing between the first groove andthe second groove adjacent to the first groove is greater than 20 μm,and the spacing between the first groove and the hollowed-out groove isgreater than 20 μm.

In some possible implementations, the display substrate further includesan organic encapsulation layer disposed on the first inorganicencapsulation layer and a second inorganic encapsulation layer coveringthe organic encapsulation layer, the second inorganic encapsulationlayer covers the first inorganic encapsulation layer at the position ofthe groove structure.

In some possible implementations, the size of the hollowed-out groove islarger than the size of the display region in a direction along thelength of the hollow groove, and both ends of the hollowed-out grooveprotrude beyond the boundary of the display region.

In some possible implementations, the size of the groove structure islarger than the size of the display region in a direction along thelength of the groove structure, and both ends of the groove structureprotrude beyond the boundary of the display region.

In some possible implementations, the size of the first groove and thesecond groove are both larger than the size of the display region alongthe length direction of the groove structure, and both ends of the firstgroove and the second groove protrude beyond the boundary of the displayregion.

In another aspect, an embodiment of the present application furtherprovides a method for preparing a display substrate, including: forminga first organic base layer on a hard carrier plate, the first organicbase layer having a hollowed-out groove exposing the hard carrier plateand a groove structure located between the hollowed-out groove and adisplay region; forming a light-emitting unit in the display region onthe first organic base layer, the first organic base layer being exposedin an region other than the display region; depositing a first inorganicencapsulation film on the hard carrier plate on which the light-emittingunit is formed, the first inorganic encapsulation film covering thegroove structure; and stripping the hard carrier plate to form thedisplay substrate.

In some possible implementations, forming a first organic base layer ona hard carrier plate includes: coating a flexible material on the hardcarrier plate, curing the flexible material into a film to form a secondorganic base film; depositing a barrier film on the second organic basefilm, removing the barrier film at the position of the hollowed-outgroove through a patterning process to form a barrier layer; coating aflexible material on the hard carrier plate on which the barrier layeris formed, and curing the flexible material into a film to form a firstorganic base film; patterning the first organic base film and the secondorganic base film by a photolithography process to form a hollowed-outgroove exposing the hard carrier plate, and forming a groove structurebetween the hollowed-out groove and a display region on the firstorganic base film.

In yet another aspect, an embodiment of the present disclosure alsoprovides a display device, which includes a display substrate, thedisplay substrate includes a display region and hollowed-out groovesprovided on a periphery of the display region; the display substrateincludes a base structure layer and a light-emitting unit provided onthe base structure layer and located in the display region; the basestructure layer includes a first organic base layer; the light-emittingunit is provided on the first organic base layer; the first organic baselayer is provided with a groove structure located between thehollowed-out groove and the display region, and the display substratefurther includes a first inorganic encapsulation layer covering thelight-emitting unit and the groove structure.

In some possible implementations, the base structure layer furtherincludes a barrier layer disposed on a side of the first organic baselayer facing away from the light-emitting unit and a second organic baselayer disposed on a side of the barrier layer facing away from the firstorganic base layer.

In some possible implementations, the groove structure includes a firstgroove exposing the barrier layer, and the first inorganic encapsulationlayer is in direct contact with the barrier layer at the first groove.

Other features and advantages of the technical solutions of the presentdisclosure will be set forth in the description which follows, and inpart will become apparent from the description, or be learned bypractice of the technical solutions of the present disclosure. Purposesand other advantages of the technical solutions of the presentdisclosure may be realized and obtained by structures specificallypointed out in the specification, claims and drawings.

BRIEF DESCRIPTION OF DRAWINGS

Accompanying drawings are used to provide a further understanding oftechnical solutions of the present disclosure, form a part of thespecification, and explain technical solutions of the present disclosuretogether with embodiments of the present disclosure, while they do notconstitute a limitation on the technical solutions of the presentdisclosure.

FIG. 1 is a schematic top view of a structure of a stretchable displaysubstrate.

FIG. 2 is a schematic structural diagram of A-A section in FIG. 1 .

FIG. 3 is a schematic top view of a structure of a display substrateaccording to an exemplary embodiment of the present disclosure.

FIG. 4 is a schematic structural diagram of B-B section in FIG. 3 .

FIG. 5 is a schematic diagram of a structure of a display substrateafter a base structure layer is formed.

FIG. 6 is a schematic diagram of a structure of a display substrateafter a driving structural layer is formed.

FIG. 7 is a schematic diagram of a structure of a display substrateafter a light-emitting unit is formed.

FIG. 8 is a schematic diagram of a structure of a display substrateafter a second inorganic encapsulation film is formed.

FIG. 9 is a schematic diagram of an overall top view structure of adisplay substrate according to an exemplary embodiment of the presentdisclosure.

DETAILED DESCRIPTION

In order to make the objects, technical solutions and advantages of thepresent disclosure clearer, embodiments of the present disclosure willbe described in detail below with reference to the accompanyingdrawings. Those skilled in the art should understand that embodimentsand features in the embodiments in the present disclosure may becombined with each other arbitrarily if there is no conflict.

In a stretchable OLED product, an OLED display panel includes multipledisplay regions arranged in an array, each display region is providedwith multiple OLED light-emitting units, and a hollowed-out groove isformed between adjacent display regions, so that when the display panelis stretched, the hollowed-out grooves are deformed to prevent thestretching from affecting the display of the display regions.

The flexible substrate of the stretchable OLED display panel includes anorganic base layer on which OLED light-emitting units are provided. Inorder to improve the stretchability of the stretchable display panel,the stretchable display panel is provided with hollowed-out groovesaround the display region. The organic base layer is made of a materialwith poor water resistance, and a part of the side surface of theorganic base layer is exposed through the hollowed-out groove, so thatwater and oxygen easily invade into the organic base layer from thehollowed-out groove and further invade into the OLED light-emittingunits, thus affecting the service life of the display panel.

FIG. 1 is a schematic top view a structure of a stretchable displaysubstrate, and FIG. 2 is a schematic structural view of A-A section inFIG. 1 . As shown in FIGS. 1 and 2 , the stretchable display substrateincludes multiple display regions 11 (a region surrounded by a dottedline frame 11′) arranged in an array, multiple light-emitting units 23are provided in the display region 11, the light-emitting units 23 areusually OLED light-emitting units. A hollowed-out groove 12 is providedbetween adjacent display regions 11.

As shown in FIG. 2 , the stretchable display substrate includes a basestructure layer 21, a driving structure layer (not shown in the Figure),a light-emitting unit 23, and an encapsulation structure layer 24. Thedriving structure layer is located on a side surface of the basestructure layer 21, the light-emitting unit 23 is located on the side ofthe driving structure layer facing away from the base structure layer 21and is electrically connected with the thin film transistor in thedriving structure layer, and both the driving structure layer and thelight-emitting unit 23 are located in the display region 11. Theencapsulation structure layer 24 is disposed on the base structure layer21 on which the light-emitting unit 23 is formed, and the encapsulationstructure layer 24 covers the display region 11. As shown in FIG. 2 ,the base structure layer 21 may include a second organic base layer 211,a barrier layer 212 and a first organic base layer 213 from bottom totop. The encapsulation structure layer 24 may include a first inorganicencapsulation layer 241, an organic encapsulation layer 242, and asecond inorganic encapsulation layer 243 from bottom to top. Theorthographic projections of the first inorganic encapsulation layer 241and the second inorganic encapsulation layer 243 on the base structurelayer 21 coincide, and the orthographic projection of the organicencapsulation layer 242 on the base structure layer 21 is within therange of the orthographic projection of the second inorganicencapsulation layer 243 on the base structure layer 21.

In the stretchable display substrate shown in FIGS. 1 and 2 , the firstorganic base layer 213 has an exposed end face 100 exposed through thehollowed-out groove 12 due to the existence of the hollowed-out groove12. The material (e.g., polyimide, etc.) of the first organic base layer213 has poor water resistance. Although a small amount of inorganicmaterial is deposited on the exposed end face 100 to form a protectivefilm when forming the first inorganic encapsulation layer 241 and thesecond inorganic encapsulation layer 243, the protective film is verythin and cannot block water and oxygen very well, water and oxygen maystill invade the first organic base layer 213 from the exposed end face100 and further invade the light-emitting unit 23, affecting the servicelife of the stretchable display substrate.

In order to solve the above technical problems, an embodiment of thepresent disclosure provides a display substrate. The display substrateincludes a display region and hollowed-out grooves provided on theperiphery of the display region. The display substrate includes a basestructure layer, a light-emitting unit provided on the base structurelayer and located in the display region, the base structure layerincludes a first organic base layer, the light-emitting unit is providedon the first organic base layer, the first organic base layer isprovided with a groove structure located between the hollowed-outgrooves and the display region, and the display substrate furtherincludes a first inorganic encapsulation layer covering thelight-emitting unit and the groove structure.

FIG. 3 is a schematic top view of a structure of a display substrate inan exemplary embodiment of the present disclosure, and FIG. 4 is aschematic structural diagram of a section B-B in FIG. 3 . As shown inFIG. 3 , the display substrate includes a display region 11 (a regionsurrounded by a dotted line frame 11′), the periphery of the displayregion 11 is provided with hollowed-out grooves 12, at least onelight-emitting unit 23 is provided in the display region 11, and thelight-emitting unit 23 may include an OLED light-emitting unit. As shownin FIG. 4 , the display substrate includes a base structure layer 21,which may include a first organic base layer 213. The first organic baselayer 213 is provided with a groove structure, and the groove structureis located between the hollowed-out groove 12 and the display region 11.The display substrate further includes a driving structure layer (notshown in the Figure) disposed on the first organic base layer 213. Thedriving structure layer is located in the display region 11 and includesa thin film transistor. The light-emitting unit 23 is provided on thedriving structure layer and located in the display region 11, and thelight-emitting unit 23 is electrically connected with a correspondingthin film transistor of the driving structure layer. The displaysubstrate further includes an encapsulation structure layer 24 coveringthe light-emitting unit 23. The encapsulation structure layer 24 coversthe display region 11, and the encapsulation structure layer 24 includesa first inorganic encapsulation layer 241 covering the light-emittingunit 23 and the exposed surface of the groove structure.

Those skilled in the art can understand that, as shown in FIG. 4 , thefirst organic base layer 213 has an exposed end face 100 exposed througha hollow groove. Although a small amount of inorganic material coversthe exposed end face 100 when forming the first inorganic encapsulationlayer 241, the inorganic material covering the exposed end face 100 isvery thin and cannot block water and oxygen very well. In the displaysubstrate of an embodiment of the present disclosure, a groove structurelocated between the hollowed-out groove 12 and the display region 11 isformed on the first organic base layer 213, and the first inorganicencapsulation layer 241 covers the exposed surface of the groovestructure. Thus when water and oxygen invade from the exposed end face100 of the first organic base layer 213, the provision of the firstinorganic encapsulation layer 241 makes the cross section of the firstorganic base layer 213 in the direction perpendicular to the water andoxygen intrusion path (i.e., in the direction perpendicular to thehorizontal direction) become smaller at the position of the groovestructure, i.e., the provision of the first inorganic encapsulationlayer 241 makes the cross section of the first organic base layer 213 inthe vertical direction become smaller at the position of the groovestructure, thereby blocking a part of the water and oxygen from invadinginto the first organic base layer 213 close to the display region, andfurther blocking the water and oxygen from invading into thelight-emitting unit 23, reducing the influence on the service life ofthe display substrate, and prolonging the service life of the displaysubstrate.

In an exemplary embodiment, as shown in FIG. 4 , the base structurelayer 21 may further include a barrier layer 212 disposed on a side ofthe first organic base layer 213 facing away from the light-emittingunit and a second organic base layer 211 disposed on a side of thebarrier layer 212 facing away from the first organic base layer 213.Such base structure layer has good flexibility and rigidity, and isfavorable for stripping the display substrate from the hard carrierplate during the subsequent stripping from the hard carrier plate.

Those skilled in the art can understand that each light-emitting unit 23may include sub-pixel units of at least three colors, e.g., R, G, B.Each sub-pixel unit is electrically connected with a corresponding thinfilm transistor in the driving structure layer respectively, so thateach sub-pixel unit can realize independent switch control and display.

In an exemplary embodiment, as shown in FIG. 4 , the groove structuremay include a first groove 31 through which the barrier layer 212 isexposed. In the first groove 31 of this structure, when the firstinorganic encapsulation layer 241 covers the exposed surface of thegroove structure, the first inorganic encapsulation layer 241 covers theexposed surface of the first groove 31, that is, the first inorganicencapsulation layer 241 is in directly contact with the barrier layer212 at the first groove 31, so that the first inorganic encapsulationlayer 241 completely blocks the first organic base layer located at bothsides of the first groove 31, preventing water and oxygen from invadinginto the first organic base layer close to the display region throughthe exposed end face 100, thus preventing water and oxygen from invadinginto the light-emitting unit 23, and ensuring the service life of thedisplay substrate.

In an exemplary embodiment, as shown in FIG. 4 , the groove structuremay further include a second groove 32 located between the first groove31 and the display region 11, and the depth of the second groove 32 issmaller than the depth of the first groove 31. When the first inorganicencapsulation layer 241 covers the exposed surface of the groovestructure, the first inorganic encapsulation layer 241 covers theexposed surface of the second groove 32. The depth of the second groove32 is ¼ to ½ of the thickness of the base structure layer 21.

In an exemplary embodiment, the number of second grooves 32 may be oneor more. When there are multiple second grooves 32, the multiple secondgrooves may be sequentially provided in a region between the firstgroove 31 and the display region 11, and the depths of the multiplesecond grooves may be sequentially decreased in the direction from thefirst groove 31 toward the display region 11. For example, as shown inFIG. 4 , the number of second grooves 32 is 2. In the direction from thefirst groove 31 toward the display region 11, the depth of the secondgroove 322 is smaller than the depth of the second groove 321. In anexemplary embodiment, the depth of the second groove 321 is 8 μm, andthe depth of the second groove 322 is 6 μm. Those skilled in the art canunderstand that the depth of the groove is the size of the groove in adirection perpendicular to the display substrate.

During the stretching of the display substrate, the second groove 32 maybe provided to serve as a stretching buffer region, so as to reduce thedamage of the stretching stress to the first inorganic encapsulationlayer 241. In addition, the first inorganic encapsulation layer 241covering the exposed surface of the second groove 32 may further blockthe lateral water and oxygen to prevent the water and oxygen fromentering the first organic base layer 213 through the side surface ofthe second groove.

In an exemplary embodiment, as shown in FIG. 4 , the spacing betweenadjacent second grooves is greater than 20 μm, and the spacing d1between the first groove and the second groove adjacent thereto is alsogreater than 20 μm. The spacing d2 between the first groove 31 and thehollowed-out groove 12 is larger than 20 μm. Setting the spacing to begreater than 20 μm is beneficial to forming complete first groove andsecond groove, thus improving the product yield.

In order to ensure that the first inorganic encapsulation layer 241covers the surface of the groove structure, as shown in FIG. 4 , in thedirection from the barrier layer 212 toward the first organic base layer213, the longitudinal section shapes of the first groove and the secondgroove are both open shapes with the opening gradually increasing, here,the longitudinal section is a section perpendicular to the lengthdirection of the first groove or the second groove. Therefore, when thefirst inorganic encapsulation layer 241 is formed, the first inorganicencapsulation layer 241 may be uniformly deposited and distributed onthe exposed surfaces of the first groove and the second groove, therebypreventing a rift on the first inorganic encapsulation layer 241 on theside surface of the groove and preventing water and oxygen from enteringthe first organic base layer 213 from the groove.

In an exemplary embodiment, the cross section of the groove may beinverted trapezoidal, as shown in FIG. 4 . The cross sections of thefirst groove 31 and the second groove 32 are both inverted trapezoidal.

In an exemplary embodiment, the base structure layer 21 includes asecond organic base layer 211, a barrier layer 212 disposed on thesecond organic base layer 211, and a first organic base layer 213disposed on the barrier layer 212. The entire thickness of the basestructure layer 21 may be 10 μm to 50 μm. The thickness of the secondorganic base layer 211 may be 8 μm to 12 μm, for example, the thicknessof the second organic base layer 211 may be one of 8 μm, 9 μm, 10 μm, 11μm and 12 μm; the thickness of the barrier layer 212 may be 0.05 μm to2.5 μm, for example, the thickness of the barrier layer 212 may be oneof 0.05 μm, 0.1 μm, 0.5 μm, 1.0 μm, 1.5 μm, 2.0 μm, 2.5 μm; thethickness of the first organic base layer 213 may be 8 μm to 12 μm, forexample, the thickness of the first organic base layer 213 may be one of5 μm, 9 μm, 10 μm, 12 μm. The materials of the second organic base layer211 and the first organic base layer 213 may be the same, for example,each may include at least one of the following materials: polyimide PI,polyethylene terephthalate PET, and a surface-treated polymer soft film,etc. The material of the barrier layer 212 may include a material havinga function of blocking water and oxygen. For example, the material ofthe barrier layer 212 may include at least one of silicon nitride,silicon oxide, silicon carbide (SiC), aluminum oxide (Al₂O₃), ZnS, ZnO,and the like.

In an exemplary embodiment, the encapsulation structure layer 24 mayfurther include an organic encapsulation layer 242 and a secondinorganic encapsulation layer 243. The organic encapsulation layer 242is disposed on the first inorganic encapsulation layer 241, thethickness of the organic encapsulation layer 242 may be 10 μm to 20 μm,and the second inorganic encapsulation layer 243 is disposed on theorganic encapsulation layer 242. The orthographic projection of theorganic encapsulation layer 242 on the base structure layer 21 is withinthe range of the orthographic projection of the first inorganicencapsulation layer 241 on the base structure layer 21. The secondinorganic encapsulation layer 243 covers the display region 11, and thesecond inorganic encapsulation layer 243 covers the surface of thegroove structure, that is, the second inorganic encapsulation layer 243covers the surface of the first inorganic encapsulation layer 241located at the position of the groove structure. In such a structure,two inorganic material layers are disposed at the groove structure, thusenhancing the blocking effect on water and oxygen.

In another embodiment, the encapsulation structure layer may includemore inorganic encapsulation layers and organic encapsulation layers,the encapsulation structure layer is a structure in which inorganicencapsulation layers and organic encapsulation layers are alternatelystacked, a layer of the encapsulation structure layer close to thelight-emitting unit is an inorganic encapsulation layer, and a layeraway from the light-emitting unit is also an inorganic encapsulationlayer.

In an exemplary embodiment, as shown in FIG. 3 , in the length directionof the hollowed-out groove 12 (i.e., the extending direction of thehollowed-out groove), the size of the hollowed-out groove 12 is largerthan the size of the display region 11, and both ends of thehollowed-out groove 12 protrude beyond the boundary of the displayregion 11. In the process of stretching the display substrate, suchhollowed-out groove is deformed, the display region is prevented frombeing stretched, the display region is well protected, and theperformance of the display substrate is ensured.

In an exemplary embodiment, as shown in FIG. 3 , in the length directionof the groove structure (i.e., the extending direction of the groovestructure), the size of the groove structure is larger than the size ofthe display region, and both ends of the groove structure protrudebeyond the boundary of the display region 11. In an exemplaryembodiment, as shown in FIG. 3 , in the extending direction of thegroove structure, the size of the first groove 31 is larger than thesize of the display region, and both ends of the first groove 31protrude beyond the boundary of the display region. The size of thesecond groove 32 is larger than the size of the display region, and bothends of the second groove 31 protrude beyond the boundary of the displayregion. With such a structure, water and oxygen can be completelyblocked from entering the display region along the horizontal direction,and the water and oxygen resistance of the display substrate is betterenhanced.

An embodiment of the present disclosure also provides a method forpreparing the display substrate shown in FIG. 4 , which may include:forming a first organic base layer on a hard carrier plate, the firstorganic base layer having a hollowed-out groove exposing the hardcarrier plate and a groove structure located between the hollowed-outgroove and a display region; forming a light-emitting unit in a displayregion on the first organic base layer, the first organic base layerbeing exposed in an region other than the display region; depositing afirst inorganic encapsulation film on the hard carrier plate on whichthe light-emitting unit is formed, the first inorganic encapsulationfilm covering the groove structure; and stripping the hard carrier plateto form the display substrate.

The technical solutions of embodiments of the present disclosure aredescribed below in detail through the preparation process of the displaysubstrate. Among them, the “patterning process” in the presentdisclosure includes processes such as depositing a film layer, coatingphotoresist, mask exposure, development, etching, stripping photoresist,the “photolithography process” in the present disclosure includesprocesses such as mask exposure, development, and evaporation,deposition, coating, applying, etc. in the present disclosure are maturepreparation processes in related technologies.

In an exemplary embodiment, the preparing process of the displaysubstrate may include the following operations.

(1) A first organic base layer is formed on a hard carrier plate, whichspecifically includes: coating a flexible material on the hard carrierplate 1, curing the flexible material into a film, to form a secondorganic base film; depositing a barrier film on a second organic basefilm, patterning the barrier film through a patterning process, removingthe barrier film at the position of the hollowed-out groove 12, to forma barrier layer 212; coating a flexible material on the hard carrierplate 1 on which the barrier layer 212 is formed, curing the flexiblematerial into a film, to form a first organic base film, and patterningthe first organic base film and the second organic base film by using aphotolithography process to form a first organic base layer 213 and asecond organic base layer 211, as shown in FIG. 5 , FIG. 5 is aschematic diagram of a structure of a display substrate after a basestructure layer is formed. The thickness of the formed second organicbase film may be 10 μm, the thickness of the barrier layer may be 0.5μm, and the thickness of the first organic base film may be 10 μm.

In this photolithography process, the first organic base film and thesecond organic base film located at the position of the hollowed-outgroove 12 are completely removed to form the hollowed-out groove 12, andthe first organic base layer has an exposed end face 100 exposed throughthe hollowed-out groove 12; the first organic base film at the positionof the first groove 31 is completely removed to form the first groove 31through which the barrier layer 212 is exposed; the first organic basefilm at the position of the second groove 32 is partially removed toform the second groove 32. Since the materials of the second organicbase layer 211 and the first organic base layer 213 are both flexiblematerials, the formed substrate structure layer is a flexible substrate.The flexible materials may include at least one of the followingmaterials: polyimide PI, polyethylene terephthalate PET, andsurface-treated polymer soft film, etc. The barrier film may be made ofa material having a water and oxygen blocking effect, for example, atleast one of silicon nitride, silicon oxide, silicon carbide (SiC),aluminum oxide (Al₂O₃), ZnS, ZnO and the like.

In order to make the side surface of the hollowed-out groove 12vertical, in an exemplary embodiment, the hollowed-out groove 12 may beformed by a plasma etching process. For example, a metal mask layer maybe formed on the first organic base film, the position of thehollowed-out groove 12 is exposed, the position of the hollowed-outgroove 12 is etched by a plasma etching process to form a hollowed-outgroove with the side being nearly vertical, and then the metal masklayer is removed. Then the first groove and the second groove are formedby a photolithography process.

(2) A driving structure layer 22 located in the display region is formedon the first organic base layer, as shown in FIG. 6 . FIG. 6 is aschematic diagram of the structure of the display substrate after thedriving structure layer is formed. In the following, with reference toFIG. 6 , the process of forming the driving structure layer will beexplained by taking the top gate type thin film transistor as anexample. Forming a driving structure layer on the first organic baselayer includes: depositing an active thin film on the first organic baselayer, and patterning the active thin film through a patterning processto form an active layer located in a display region. In this patterningprocess, the active thin film at a position other than the position ofthe active layer is etched away, exposing the first organic base layer213.

A first insulating film and a gate metal film are sequentially depositedon the hard carrier plate 1 on which the active layer is formed, and thegate metal film is patterned by a patterning process to form a gateelectrode and a gate line (not shown in the figure) located in a displayregion. In this patterning process, the gate metal film at a positionother than the position of the gate electrode and the gate line isetched away, exposing the first insulating film.

A second insulating film is deposited on the first insulating film onwhich the gate electrode is formed, and the second insulating film andthe first insulating film are patterned by a patterning process to forma second insulating layer (also referred to as an interlayer insulatinglayer) and a first insulating layer (also referred to as a gateinsulating layer) located in a display region, as shown in FIG. 6 . Thefirst insulating layer and the second insulating layer are provided witha first via hole and a second via hole, and the active layer is exposedthrough the first via hole and the second via hole. In this patterningprocess, the second insulating film and the first insulating filmlocated in the region other than the display region are etched away,exposing the first organic base layer 213 and the hollowed-out groove12.

A second metal film is depositing on the hard carrier plate 1 on whichthe second insulating layer is formed, and the second metal film ispatterned by a patterning process to form a source electrode, a drainelectrode and a data line (not shown in the figure), the sourceelectrode and the drain electrode are electrically connected with theactive layer through the first via hole and the second via holerespectively. In this patterning process, the second metal film at aposition other than the position of the source electrode, drainelectrode and data line is etched away, exposing the first organic baselayer 213 and the hollowed-out groove 12 in the region other than thedisplay region.

A flat layer located in the display region is formed on the hard carrierplate on which the source electrode and the drain electrode are formed,a third via hole for exposing the drain electrode is provided on theflat layer, and the first organic base layer 213 and the hollowed-outgroove 12 are exposed in the region other than the display region, asshown in FIG. 6 .

Those skilled in the art can understand that the first insulating filmand the second insulating film are both made of silicon oxide or/andsilicon nitride materials, and the silicon oxide and silicon nitridematerials have the function of blocking water and oxygen, so in theprocess of patterning the first insulating film and the secondinsulating film, only the first insulating film and the secondinsulating film at the positions of the first via hole and the secondvia hole may be removed, and the first insulating film and the secondinsulating film at other positions may be reserved. At this time, thefirst insulating film and the second insulating film retained at thepositions of the first groove 31 and the second groove 32 can completelyblock the first organic base layer located at both sides of the firstgroove 31, preventing water and oxygen from invading into the firstorganic base layer close to the display region through the exposed endface 100. When the first insulating film and the second insulating filmare retained at the first groove and the second groove, the subsequentlyformed first inorganic encapsulation layer may directly cover thesurface of the second insulating film at the positions of the firstgroove and the second groove.

(3) A light-emitting unit 23 located in the display region is formed onthe driving structure layer 22. The light-emitting unit 23 may be anOLED light-emitting unit. The first organic base layer 213 and thehollowed-out groove 12 are exposed in the region other than the displayregion, as shown in FIG. 7 , FIG. 7 is a schematic diagram of thestructure of the display substrate after the light-emitting unit isformed. Those skilled in the art may understand that the process offorming the light-emitting unit 23 may include the steps of sequentiallyforming an anode, a pixel defining layer, an organic light-emittinglayer and a cathode, and the light-emitting unit 23 may be formed byusing conventional processes and methods in the art, which will not berepeated again.

(4) An encapsulation structure layer 24 is formed on the hard carrierplate 1 on which the light-emitting units 23 are formed, as shown inFIG. 8 , FIG. 8 is a schematic diagram of a structure of a displaysubstrate after a second inorganic encapsulation film is formed. Thisstep may include: depositing a first inorganic encapsulation film on thehard carrier plate 1 on which the light-emitting unit 23 is formed, andcovering, by the first inorganic encapsulation film, the surfaces of thefirst groove 31 and the second groove 32.

An organic encapsulation layer 242 is formed on the first inorganicencapsulation film, and the orthographic projection of the organicencapsulation layer 242 on the base structure layer surrounds theorthographic projection of the display region on the base structurelayer. The material of the organic encapsulation layer 242 can be amixture of a Monomer organic main body (more than 95% in volume) and aphotoinitiator, a reactive diluent, various additives and the like, andcan be formed into a film by ink jet printing and cured underultraviolet light irradiation to form the organic encapsulation layer242. The thickness of the organic encapsulation layer 242 can be 10 μmto 20 μm.

A second inorganic encapsulation film is deposited on the firstinorganic encapsulation film on which the organic encapsulation layer242 is formed, and the second inorganic encapsulation film covers thesurfaces of the first inorganic encapsulation film at the positions ofthe first groove 31 and the second groove 32.

The materials of the first inorganic encapsulation film and the secondinorganic encapsulation film may include materials having a water andoxygen blocking effect, for example, at least one of silicon nitride,silicon oxide, silicon carbide (SiC), aluminum oxide (Al₂O₃), ZnS, ZnOand the like. The first inorganic encapsulation film and the secondinorganic encapsulation film may be formed by means of chemical vapordeposition (CVD), atomic layer deposition (ALD) and other depositionmodes, and the thicknesses of the first inorganic encapsulation film andthe second inorganic encapsulation film may be 0.05 μm to 2.5 μm.

(5) Finally, the hard carrier plate 1 is stripped to form thestretchable flexible OLED display substrate according to an embodimentof the present disclosure, as shown in FIG. 4 . Wherein, since the firstinorganic encapsulation film and the second inorganic encapsulation filmat the position of the hollowed-out groove are directly formed on thehard carrier plate 1, when the hard carrier plate 1 is stripped, thefirst inorganic encapsulation film and the second inorganicencapsulation film are stripped together from the position of thehollowed-out groove, thereby forming the first inorganic encapsulationlayer 241 and the second inorganic encapsulation layer 243 as shown inFIG. 4 . The second inorganic encapsulation film and the first inorganicencapsulation film covering the exposed end face of the base structurelayer are retained. The orthographic projection of the organicencapsulation layer 242 on the base structure layer 21 is within therange of the orthographic projection of the first inorganicencapsulation layer 243 on the base structure layer 21.

Those skilled in the art may understand that the display substrateprepared with the above preparation method is a top-emitting OLEDdisplay substrate. The method for preparing a display substrate providedby an embodiment of the disclosure may also be applied to abottom-emitting OLED display substrate. For the bottom-emitting OLEDdisplay substrate, the method of forming each film layer on a firstorganic base layer is a well-known technology in the art, and thebeneficial effects of embodiments of the present disclosure can beachieved as long as the formed first inorganic encapsulation film coversthe groove structure.

FIG. 9 is a schematic diagram of an overall top view structure of adisplay substrate in an exemplary embodiment of the disclosure. As shownin FIG. 9 , the display substrate includes multiple display regions 11arranged in an array, a hollowed-out groove 12 is located betweenadjacent display regions 11, and the display substrate is a stretchableOLED display substrate.

An embodiment of the disclosure also provides a display device, whichincludes the display substrate adopting the previous embodiment. Thedisplay device may be any product or component with a display functionsuch as a mobile phone, a tablet computer, a television, a display, anotebook computer, a digital photo frame, a navigator.

In the description of the present disclosure, it should be understoodthat an orientation or position relationship indicated by terms“middle”, “upper”, “lower”, “front”, “rear”, “vertical”, “horizontal”,“top”, “bottom”, “inside”, “outside” or the like is based on theorientation or position relationship shown in the drawings, and this isonly for ease of description of the present disclosure andsimplification of the description, rather than indicating or implyingthat the referred apparatus or element must have a specific orientation,or be constructed and operated in a particular orientation, andtherefore this cannot be interpreted as a limitation on the presentdisclosure.

In the description of embodiments of present disclosure, it should benoted that unless otherwise clearly specified and defined, terms“install”, “connect” and “link” should be broadly interpreted, forexample, it may be fixedly connected, or may be removable connected, ormay be integrally connected; it may be mechanically connected, or may beelectrically connected; it may be directly connected, or may beindirectly connected through an intermediate medium, or it may be aninternal connection of two elements. For those of ordinary skill in theart, the specific meanings of the above terms in the present disclosuremay be understood according to a specific situation

Although the embodiments disclosed in the present disclosure are as theabove, the contents are only embodiments for facilitating understandingthe present disclosure, rather than for restricting the presentdisclosure. Any person skilled in the field to which the presentdisclosure pertains may make any modifications and variations in theforms and details of implementation without departing from the spiritand the scope disclosed by the present disclosure. However, the patentprotection scope of the present disclosure shall still be subject to thescope defined by the appended claims.

What is claimed is:
 1. A method for preparing a display substrate,wherein the display substrate comprises a plurality of display regionsarranged in an array and a plurality of hollowed grooves provided on aperiphery of the display regions; the hollowed grooves are formedbetween adjacent display regions respectively, in a case that thedisplay substrate is stretched, the hollowed grooves are deformed, themethod comprising: forming a first organic base layer, a second organicbase layer and a barrier layer on a hard carrier plate, the firstorganic base layer having a hollowed groove of the plurality of hollowedgrooves exposing the hard carrier plate and a groove structure locatedbetween the hollowed groove and a display region of the plurality ofdisplay region, wherein the barrier layer is disposed on the secondorganic base layer, and the first organic base layer is disposed on aside of the barrier layer facing away from the second organic baselayer, forming a light-emitting unit in the display region on the firstorganic base layer, the first organic base layer being exposed in aregion other than the display region; depositing a first inorganicencapsulation film on the hard carrier plate on which the light-emittingunit is formed, the first inorganic encapsulation film covering thegroove structure; and stripping the hard carrier plate to form thedisplay substrate, wherein: the first inorganic encapsulation layer isin direct contact with the barrier layer at a first groove of the groovestructure, the first organic base layer located at both sides of thefirst groove is completely blocked by the first inorganic encapsulationlayer, and the first organic base layer comprises an exposed surface,the exposed surface is exposed at a location of the hollowed grooves;the groove structure further comprises a plurality of second grooves,the plurality of second grooves is sequentially provided in a regionbetween the first groove and the display regions, and depth of theplurality of second grooves is sequentially decreased in a directionfrom the first groove toward the display regions; in a direction fromthe barrier layer toward the first organic base layer, shapes oflongitudinal sections of the first groove and the second grooves areboth open shapes with an opening gradually increasing, wherein thelongitudinal sections are sections perpendicular to a length directionof the first groove or the second grooves; and a length of the hollowedgrooves is longer than lengths of the first groove and the secondgrooves.
 2. The method for preparing according to claim 1, whereinforming the first organic base layer on the hard carrier platecomprises: coating a flexible material on the hard carrier plate, curingthe flexible material into a film to form a second organic base film;depositing a barrier film on the second organic base film, removing thebarrier film at a position of the hollowed groove through a patterningprocess to form a barrier layer; coating a flexible material on the hardcarrier plate on which the barrier layer is formed, curing the flexiblematerial into a film to form a first organic base film; and patterningthe first organic base film and the second organic base film by aphotolithography process to form the hollowed groove exposing the hardcarrier plate, and forming a groove structure between the hollowedgroove and a display region on the first organic base film.